Patent Citation 1 discloses a remote copy system that carries out data replication management (remote copy) superior in fault-tolerance at low cost, in which the remote copy system includes a first memory system coupled to a first superior computer system, a second memory system that is coupled to the first memory system to receive data from the first memory system, and a third memory system that is coupled to the second memory system to receive data from the second memory system and that is coupled to a second superior computer system to exchange data with the second superior computer system as well. The remote copy system reads data and updated information written on a second storage area from the third memory system after a lapse of a given time to write to a third storage area the data and updated information.
[Patent Citation 1]
    Japanese Patent Application Laid-Open Publication No. 2006-099440